Due to the complexity of the organization of eukaryotic cells model systems for studying cell differentiation have been sought in prokaryotic systems; one such system proving to be an excellent model is that of bacterial spore germination and sporulation. The germination system is a defined one that can be made synchronous and the direction of development is easily manipulated. One such manipulation is that of causing an outgrowing cell to form a spore without first going through an intervening symmetrical cell division. This normal "bypass" in the spore-to-spore cycle, first described in this laboratory and termed microcycle sporulation, has been used to develop a system to study the processes of sporulation induction. Our approaches to this problem are based on our hypothesis that the initial developmental sequences leading to spore formation represent a modified cell division with the division septum being constructed in an asymmetrical position in the cell. We are investigating the mechanism(s) involved in asymmetrical versus symmetrical division. The probes outlined in this proposal are directed towards gaining such information. We will investigate the relationship between the DNA cycle and sporulation induction. Specifically we are asking what role the chromosome has in septum formation. It is suggested that elongation of bacilli is achieved by growth from a specific membrane growth site and we are interested in relating the development of such a growth site to both asymmetrical and symmetrical division. BIBLIOGRAPHIC REFERENCES: Slee, A. M., M. Mychajlonka, S. C. Holt, and R. A. Slepecky. 1977. Characterization of patterns of symmetrical and asymmetrical division in outgrowing cells of Bacillus megaterium. p. 85-92. In Schlessinger, D. (Ed.) Microbiology 1977, American Society for Microbiology, Washington. Slepecky, R. A. and E. R. Leadbetter. 1977. The diversity of spore-forming bacteria: some ecological implications. In A. N. Barker, G. W. Gould and J. Wolf (Ed.), Spore Research 1976, Academic Press, London, in press.